Lightning arrester



Dec. 19, 1922.

G. R. FOLDS.

LIGHTNING ARRESTER.

2 SHEETS-SHEET l.

FILED JULY 12. 1919.

i B? IyEIIVTOR. i i/ Z goRA E Y5.

Dec. 19, 1922. 1,438,953.

G. R. FOLDS. LIGHTNING ARRESTER.

FILED J ULY 12, 1919- v 2 SHEETSSHEET 2- W W, M TTORNE Ks atented Dec;19, 1922.

UNITED STATES PATENT OFFICE.

GEORGE R. FOLDS, OF EVANS'ION, ILLINOIS, ASSIGNOR TO FRANK B. COOKCOMIANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

LIGHTNING ARRESTER.

Application filed July 12,

To all whom it may concern:

Be it known that I, GEORGE R. FoLns, a citizen of the United States,residing at Evanston, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Lightning. Arresters, of whichthe following is a full, clear, concise, and exact description,reference being had to the accompanying drawing forming a part of thisspecification.

This invention relates to lightning arresters and more particularly toimproved means for electrically separating the line and ground springsof lightning arresters used on low voltage electric circuits, such astelephone, telegraph and signal systems, to provide for high potentialdischarges.

Lightning arresters used for high potential discharges on low voltageelectrical circuits are equipped with means to provide a discharge gapwhich ordinarily takes either one of two forms in commercial practice.One of these constructions comprises two conducting plates, preferablyconstructed of either carbon or copper and'separated by asuitabledielectric, the high potential jumping from one plate to the otherthrough an opening or openings provided in said dielectric. The otherform comprises what is ordinarily known as a saw-tooth arrester, inwhich a serrated or toothed edge is separated from a suitable groundplate, by the desired air space to insure the discharge of a determinedminimum potential.

It is one of the objects of this invention to provide an improved formof saw-tooth arrester construction, whereby the saw-tooth constructionmay be readily interchanged with the other construction heretobeforereferred to. This ready interchangeability between these twoconstructions provides great flexibility, that is, it makes it possibleto very readily convert an arrester from the one type to the other, thatis, from the block to the saw-tooth type. This flexibility is of greatadvantage to manufacturers, jobbers and also to the ultimate user. Thusfor example, telephone companies that are operating city as well asurban and rural telephone lines, usually find it practical to 1919.Serial No. 310,364.

use carbon block arresters at the sub-statron'sin the city and thesaw-tooth lightning arresters in the urban and rural district. In theuse of a standardized means for electrically separating the springs oflightning arresters, it becomes possible to adapt any arrester of eitherthe block or saw-tooth type and because of this ready conversion, thevaryingdemands of operating' practice can be very readily met with aminimum amount of stock, since the standard spring equipment isreadilyadapted to either the block or saw-tooth arrester separation.

Another objectof-this invention consists in the production of animproved and efiicient form of saw-tooth arrester construction which maybe readily assembled and which is low in manufacturing cost. Otherobjects of the invention will become apparent from the followingdescription, the accompanying illustrations and the appended claims.

For the purposes of description, several embodiments ofsub-station-garresters used in telephone circuits are shown in theaccompanying drawings. These areillustrative only, however, inasmuch asthe invention is adaptable to any and all forms of lightning arrestersused on low voltage circuits', such as the central station arresters,aerial-wire arresters, pole cable terminal arresters and the like.

In the drawings:

Fig. 1 illustrates aview in perspective of a substation. arresterequipped with the sawtooth spring separating means;

Fig. 2 is a side elevation thereof;

Fig. 3 is a section takenon the plan e represented bythe line.3-.-3 ofFig. 2;

F ig; 4 illustrates-a view in perspective of the arrester shown in Figsj 1 to 3 inclusive ,fitted with block type spring separating means. I

Fig. 5 illustrates in perspective the. respective parts of the saw-toothseparating means shown in Fig. 1 disassociated from one another butpositioned in the respective order in which they are combined whenplaced in position in the lightning arrester;

Fig. 6 is a similar view of the block arrester separating means;

Fig. 7 illustrates another form of sawtooth arrester separating means;and

Fig. 8 is an illustration of one of the separating blocks illustrated inFig. 7 with the parts disassociated from one another and positioned inthe respective order wh1ch they assume when assembled in an arrestermounting.

As illustrated in Figs. .1 to 3 inclusive, the arrester comprises amounting base 10 fitted with apertures 11 and 12 adapted to receivescrews for mounting the same. The base 10 is also equipped with acentral depression 13 adapted to receive the high potential protecting euipment. Mounted on the forward end 0 the mounting base 10 are the lineterminals 14 and 15 and the ground terminal 16. The line terminal 14 iselectrically and mechanically connected to a spring 17 which extendsrearwardly into the depression 13 at which point it is equipped with anupwardly extending arm 18 substantially at right angles to the mountingbase 10. The terminal 15 islikewise mechanically and electricallyconnected to a spring 19 which extends rearwardly into the depression 13and is also fitted with an. upwardly extending arm- 20 normal to themounting base. The ground terminal 16 is mechanically and electricallyconnected to a spring 21 which extends rearwardly into the depression 13and is there fitted with anupwardly extending ground plate 22. i j

The springs 17, 19 and 21 are preferably constructed ofresilientmetallic material, usually German silver. The upwardlyextending arms 18 and 20 of the springs 17 and 19 respectively areshaped in such a manner as to exert a sprlng pressure in the directionof the ground plate 22 which is situated midway between these twoupwardly extending spring arms 18 and 20.

Positioned between the spring arm 18 and the spring arm 20 and theground plate 122 on each side of said ground plate, are

the means utilized for mechanically connecting, but electricallyseparating each of these springs from the ground plate.

The apparatus used for this purpose, il lustrated in F ig..1, comprisesthe saw-tooth equipment which is illustrated in detail in Fig. Thisequipment as there shown comprises a plate 25 fitted with lateralflanges 26. and 27. The flange 27 has a serrated or saw-toothed edge, asillustrated at 28. This plate is made of conducting material, preferablysheet brass, and is equipped with the upset portions 29 and 30, whichare adapted to'properly guide'and position the plate in either of theupwardly extending spring members 18'or 20.

Positioned between the flanges 26 and 27 of theplate 25 is a dielectric31,. which is composed of some suitable non-conduct- 28.' The carbonblock 34 is positioned next to the ground plate 22 and in electricalcontact therewith. The carbon block 34 is fitted with a central slot 35whereby said block may be used either next adjacent the ground plate 22or in connection with either the springs 18 or 20 in which case the slot35 serves to position the block in its proper relationship with respectto the springs 18 and 20.

The flat surface of the carbon block 34 in contact with thenon-conducting block 32 is of greater width than the width of the plate25 and its lateral flanges 26 and 27, whereby a narrow ledge. of carbonblock surface will extend out beyond the serrated edge 28 of the plate,thereby facilitating the discharge of the high potential, and to someextent preventing the concentration of the pitting action which resultsfrom the potential discharge.

' When the various parts 25, 31, 32 and 35 are all assembled inposition, as illustrated in Fig. 1, it will beevident that the carbonblock 34 is in direct contact with the" ground terminal 16 and that theplate 25 is in direct electrical contact with either the hue terminals14 or 15 depending .upon

which side of theg-round plate the appais so designed that when it ispositioned in v the plate 25 between the flanges 26 and 27,

the top face or surface of said block will rest in substantially thesame horizontal plane as the upwardly extending points of the serratededge 28 of the flange 27 When the dielectric '31 is placed in positionunder the block 32 between the flanges 26 and 27, it will be evidentthat the serrated edge will be drawn away from the horizontal plane inwhich the top surface of the block 32 is positioned. The dielectric 31is given a thickness which is equal to the separation desired betweenthe tooth points of the serrated edge 28 and the carbon block 34 toprovide for the discharge of the minimum potential at which the arresteris designed to operate. The dielectric 31, consequently, is the meansutilized to give the desired separation between the saw-toothed edge oithe plate connected to the line terminal and the flat surface of thecarbon block 34 connected to the ground terminal 16.

A dielectric is shown in this construction inasmuch as it has beenstandard practice to use a dielectric to attain the desired separationbetween the ground and line blocks on arresters. It will be obvious,however, that the dielectric 31 could be readily dispensed with and theblock 32 so proportioned that the thickness thereof would be equal tothat of the block 32 and the thick ness of the dielectric 31. When thusdesigned, with this additional thickness, the block 32, when placed inposition between the flanges 26 and 27, will give the desired separationbetween the line plate 25 and the carbon ground block 34.

Fig. 1 shows the saw-toothed arrester block protecting means placed inposition blocks 34 separated by a dielectric such as between the lineand ground terminals. When this apparatus has been thus placed inposition to prevent foreign matter from reaching the springs and causingpossible short circuits, the apparatus is covered with a cap 36 whichrests on a ledge 37 provided in the depression 13. The cap 36 is usuallymade of some conducting metallic material and to prevent accidentalcontact between the cap and the line and ground contact springs; the capis usually lined with an insulating sleeve 38.

In Fig. 4 the same mounting base is shown which is illustrated in F igs.1 to 3 inclusive, but the arrester here shown is equipped with thestandard carbon block separating means in place of the sawtoothedseparating means illustrated in Fig. 1.

The carbon block separating means comprises the three elements,illustrated in a disassociated relationship in detail in Fig. 6. Theseelements consist of two carbon 39 or. any other'suitable commercial formof dielectric, well known to those skilled in the art. Both of the.carbon blocks used between each line spring and the ground plate, areidentical in all respects to one means.

serrated edge of the plate 25 to the carbon block 34 associated with theground plate 22.

It will be evident now from the foregoing description that the arrestershown 1n Figs. 1 to '3 inclusive and in Fig. 4 are capable of receivingeither, the saw-toothed electrical separating means consisting of theplate 25, the dielectric 31, the non-conducting block 32 and the carbonblock 34, or the carbon block separating means consisting of the twocarbon blocks 34 and the dielectric 39. In other words, the arrester isvery readily convertible from the one type to the other and themanufacturer, jobber or the ultimate operating company, by maintainingin stock carbon blocks such as 34, dielectrics such as 39 and 31, andnonconducting blocks such as 32 and plates such as 25, are in a positionto construct out of standard arrester mounting bases, and theirassociated contact springs, either carbon block or saw-toothed dischargegap lightning. arresters.

Figs. 7 and 8 illustrate another form of ground and line spring arresterseparating The mounting base and associated contact springsillustratedin Fig. 7 are the same shown in Figs. 1 to 3'inclusive. Theground spring and the line spring in this instance, however, areseparated electrically by a saw-toothed spark gap separating 'meansillustrated in detail in Fig. 8. This separating means consists of aplate 40 fitted with lateral flanges 41 and 42, each of which areserrated as indicated at 43 and 44 respectively. The plate 40 is alsoequipped with the upset'portions 45 and 46 similar to that described inconnection with the plate 25 illustrated in Fig. 5, adapted to properlycenter theplate on either of the springs 18 or 20.

Positioned on the plate 40 which is constructed of conducting material,referably sheet brass, is the dielectric 47. laced directly above thedielectric 47 is the non-con- .ductlng separating block 48 fitted withthe two lateral edge depressions 49 and 50 to provide for an increaseddischarge surface on the .carbon block 51 for the serrated edges 43 and44. These lateral edge depressions 49 and 50 serve the same purpose asthe cut away portion 33 illustrated in connection with the block 32illustrated in Figs. 1 and 5. The carbon block 51 used in connectlonwith the arrester shownin Fig.

7 is fitted with a central slot 52 adapted to properly position theblock on the line spring 18 or 20.

When the various elements or parts shown in Fig, 8 are assembled intheir relative operating positions, as shown in Fig. 7, it will beevident that the line terminals 14 and 15 are respectively connected toplates, such as 40, that the ground terminal i 16:.is connected tocarbon blocks such as 51 and that the carbon blocks 51 are separatedfrom the plates such as 40 by means of the dielectric 47 and thenon-conducting separating block 48. The high potential in thisconstruction will be discharged through the serrated edges 43 and 44 tothe carbon block 51.

When it-is desired to .convert the spark gap separating means of thearrester shown in Fig. 7 from the saw-toothed type to the carbon blocktype, it is merely necessary to use two carbon blocks such as 51separated by a suitable dielectric similar to 39 Fig. 6) on either sideof the ground plate.

onsequently the spark gap separating mieans used'with the a-rresterillustrated in Fig. 7 is likewise convertible from the carbon block typeto the saw-toothed type or vice versa.

It now follows from the foregoing description that according to theteachings in this invention, lightning arresters may be readilyconstructed which may be readily converted to meet the varying demandsof operating practice in telephone, telegraph and signalling systems,from either the carbon block to the saw-toothed type. It also followsthat due to this flexibility and ready] interchangeability, there is avery material saving in the amount of stock that must be carried to meetthe varying conditions, since the equipment is so standardized that itcan he changed at any time to meet either one of the two conditionsdesired.

Obviously, the invention is not limited to the specific embodimentsthereto herein illustrated and described, but it capable of manyvariations and other applications within the spirit and scope of theinvention as set forth in the following claims. v

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a lightning arrester, in combination, line springs and a groundplate placed in juxtaposition thereto, said springs being severallyadapted to be mechanically interconnected but electrically separatedfrom said plate by a pair of conducting blocks separated by adielectric, and-means for mechanically connecting and electricallyseparating each of said springs and plate com-- prising a conducting.plate with a serrated electric discharge edge, said conducting platebeing adapted for interchangeable insertion with one of said conductingblocks that may be received between each of said.

springs and plate.

2. In a device of the character described in combination, a metallicplate having a lateral flange, the edge of said flange being serrated,means integral with said plate adapted to properly position the plate inits operating position, a conducting block, and

a non-conducting means separating said.

adapted to properly position the plate in its.

operating position, a conducting block, and a non-conducting meansseparating. said block and said plate to provide the desired spark gapbetween said block and said serrated edge, said block being wider thansaid plate to provide a narrow ledge/which extends out beyond theserrated edge of the said plate.

4. In a device of the character described in combination, a metallicplate having 1- eral flanges, one of said flanges having a surated edge,means integral with said plate adapted to properly position the'plate inits operating position, a non-conducting means positioned'between saidflanges, and a conducting means against which said non-conducting. meansis adapted to rest, said nonconducting means maintaining the desiredseparatiton between said serrated edge and said conducting means.

5. In a device of the c aracter described in combination, a'metallicplate having lat- .eral flanges, one of said flanges having a serratededge, a non-conducting means positioned between said flanges, and aconducting means against which said non-conducting means is adapted torest, said non-conducting means maintaining the desired separationbetween said serrated edge and said conducting means and having aportion of its surfacenext ad acent sald serrated flange cut away toexpose a large surface of said conducting means. I

6. A lightning arrester comprising a metallic plate having turned-overedges one at least, of which is serrated to form a multiplicity ofelectric discharge paths, said plate incorporating integrally formedmeans for properly locating it in its operating position, anon-conducting member received in said plate between its turned-overedges and having an exposed surface that extends beyond the serratededge of said plate, and a conducting member in contact with said exposedsurface of said non-conducting meming an exposed surface subtending saidserrated edge and projecting beyond the level thereof.

8. In a device of the character described in combination, a metallicplate having lateral flanges one at least of which is provided with aserrated edge, a separating means disposed between sald flanges, aconducting means agalnst whlch sald separating means is adapted to rest,and a dielectric adapted to be positioned between said separating meansand said plate whereby a spark-gap separation may be effected betweenthe serrated edge of said plate and the said conducting means.

In Witness whereof, I have hereunuto subscribed my name.

GEORGE R. FOLDS.

